300EX motor bogging -- seems heat related -- general motor advice?

[motrrrpsycho]

I have 2003 300EX quad that I bought from the original owner a couple months ago. Had low hours and was in good shape, 100% stock. Its air cooled and has a CV type carb. Got if for my wife to ride sand dunes and for buddies to be able to come try the trails with me. Had it out for two, 30+ mile trail riding days and it ran fine. Over the weekend I was letting a buddy ride it and he rolled it hard enough to bend the bars a little, but it did not appear to do any other damage. Went back to the truck to try to rotate the bars up a little so we could keep riding, rode another couple miles and it kind of bogged down and died (while just cruising along a fire road). It was acting like it ran out of gas, but the fuel switch was on and it had plenty of gas in it. It hesitated to start, but fired back up so we kept going. Couple miles later, same thing, only it would not start. After sitting and letting it cool for 20 minutes or so we were able to start it and get it back to the truck. One person suggested that maybe it got gas in the wrong part of the carb and that I open it up and make sure it was emptied out. I tried that and let idle for a while at home and it seemed to be running good even after getting hot, so we went back out the next day. It ran good for 7 miles, then started sputtering and died again. Let it sit 20 minutes or so, ran another 4 miles, same thing, so after that decided to call it a day. It seems like whatever is happening is related to the motor getting hot. With no temp gauge or idiot lights or anything I have no idea if its getting overly hot or not. Could anyone tell me how I can tell if its getting too hot? Anyone have any ideas of what might be wrong? Thanks!!

[300ex13]

make sure your choke is off....

[motrrrpsycho]

I'm sure the choke was off, but thanks.

each time you stop are you takeing the gas cap of to check for fuel, if so it sounds like the vent is pinched or clogged or somthing, have you tried cleaning the carb, what about the aifilter, if everthing else checks out i would make some scoops

[motrrrpsycho]

I know for sure there was plenty of gas in it the whole time.

When you say vent I assume you mean the vent tube coming off the top of the tank, right? I am pretty new to off road stuff and was wondering what the purpose for those even was -- how would that cause a problem if it was pinched or clogged?

If I clean the carb, is there any certain product you suggest? Do I open up the top or bottom part or both to spray the cleaner stuff in? Do I have to remove the floats, gaskets and any non-metal parts before spraying cleaner stuff in?

Thanks! The pinched air vent sounds like a good guess since it routes through that plastic cover thing over the bars and that got smashed pretty good.

yeah the vent i was talking about is the one coming off of the gas cap, it allows air into the tank so that it doesnt create a vacum, have you ever been drinking coke and suck some up into the strw then quickly put your finger over the top of the straw, the coke goes no where its stuck in the straw, as for the carb, id just get any carb cleaner from wal mart or auto zone and spray everything doen goo but particularly any jets or little holes, hope this helps

[hondardr4life]

The vent hose sounds like the problem. That good thinkin yzfmxer, I would have never thought of that.

[motrrrpsycho]

Well, it was not the vent hose. Wish it would have been that easy. Any other ideas?

[MotoX3]

try taking your plug out and report the color...also hows the oil level?

did you clean the carb yet, see if it runs after that

[bwamos]

Make sure the red kill switch in the left bar didn't get damaged internally.

It could be that it is fine until a bump jars it just right making it ground out the coil. Since you rolled the quad and bent the bars.. it is a definate possibility.

Other than that.. make sure your battery studs didn't get cracked or messed up.

Does it try to turn over.. and just not fire?

If it does turn over, ignore the 2nd one.
If it does not turn over, ignore the 1st one.

I also assume that when you had the carb open you cleaned out all the jets with carb cleaner? If not.. some debris could have gotten knocked loose and be getting jammed into the main jet.

The 300ex's dont have a fuel filter on them stock (dont know why.).. so it's not uncommon.

[plkmonster2]

If nothings seems to fix it, your coil could be shot. They ahve that problem where they get hot, and quit working until they cool down.

[Trevor]

They do kinda have a fuel filter it is just a screen in the bottom of the fuel shut of valve. I had that clog up and cause this type of problem for me. Check that out when you have the tank off to clean the carb.

[motrrrpsycho]

Sweet, thanks guys. I have not cleaned the carb yet, but will try that and check the screen in the fuel shut off while I'm at it.

It does not look like the kill switch or anything in that area was really damaged, but I'll take a closer look. (Not sure how to test it though.) It does turn over every time, just does not fire after it has stalled until it cools down.

The plug looked OK according to one guy I asked, it was kind of blackish with carbon (isn't that normal?) but I put a new plug in anyway just in case and it made no difference. Oil level is good, although it now leaks a little oil around the drain plug cause it took a hard impact on the stock, plastic skid plate and it gave way enough to bash the drain plug -- guess I better get a metal skid plate -- any recommendations? Hope my plug and/or pan are not stripped out now...

plkmonster2 -- when you say the "coil" could be shot -- what is the coil, and how could I test that?

[plkmonster2]

The coil is the little black cylinder that is left of the motor. It is connected to the spark plug wire. To test it, when the quad starts to not run right, and when it dies, get another plug, pull the wire off, put the plug in, and ground it. Spin the motor over. It shoudl spark with a regular tempo, like spark, spark, spark, not spark spark,... spark... spark spark spark.

[motrrrpsycho]

Cleaned out my carb, and that did the trick! Does not stall anymore, and feels like it gained 25-50% HP back that I didn't know it was missing! Thanks all...

[bwamos]

Nice!
Glad you found it.